I am grateful to the community of excellent Einstein scholars, from whom I have learned just how difficult it is to write sensibly and informatively about someone literally larger than life. Among them, I recognize in particular Olivier Darrigol, Joroen van Dongen, Peter Galison, Herbert Goenner, Hanoch Gutfreund, Gerald Holton, Don Howard, Michel Janssen, Daniel Kennefick, Diana Kormos-Buchwald, Anne J. Kox, Dennis Lehmkuhl, Arthur I. Miller, John Norton, Hans C. Ohanian, Jurgen Renn, Tilman Sauer, and John Stachel. I am grateful to my colleagues, past and present, in the Department of Philosophy at Stanford for their continuous encouragement, and to Michael Friedman, Helen Longino, and Paolo Mancosu for intellectual sustenance. Heartfelt thanks to Olivier Darrigol and Arthur Fine for extremely helpful criticism and comments on drafts of various chapters. I benefitted from comments of Patrick Austin, Harald Wiltsche and Rasmus Winther while Marlene Griffiths Bagdikian assisted in turning much of a teutonically ponderous written text into passable English prose. Above all, I owe the inspiration, or audacity, to undertake this project, almost a common labor of love, to Arthur Fine: mentor, colleague, and friend.